Originally Posted by
Mad (Flt) Scientist
Even assuming you did that - and I am sure they did do the corresponding analysis, we can argue about "properly" - you'd still be left with determining the hazard classification.
I rather believe that faced with a similar failure scenario - low speed limited authority "uncommanded motion" of the stab (it's commanded, but not in the circumstances truly intended) - with the pre-existing ability to disable the system and a pre-existing procedure which would address the runaway case (if somehow it repeated) then that would probably be classified as no more than a MAJOR hazard. In other words, I strongly suspect (and this may be an unpopular view) that the system as has been presented in public information is perfectly certifiable, and I suspect analogies could be found on other aircraft.
Agreed, except "pre-existing procedure" implies there are defined criteria for DETECTING failure condition, which does not exist before the FAA AD came out. Even with the FAA AD, the flight crew identifiable symptom is a large laundry list, which is not ideal.
Similiar system on 737, STS has its own warning lamp to properly indicate failure to flight crew, per FAR25.672a clause